1. Field of the Invention
The present invention generally relates to a projection apparatus, and more particularly, to a projection apparatus with light source calibration.
2. Description of Related Art
A projection apparatus is a lightweight and small portable projector, and which can be categorized as a micro projector or a pocket projector. A pocket projector is similar to a conventional projector but has a smaller size and a lighter weight therefore can be carried around conveniently. A micro projector is even lighter and smaller therefore can be integrated into a mobile device, such as a cell phone or a digital camera.
The micro projection techniques currently adopted by micro projectors include a liquid crystal display (LCD) technique, a digital light processing (DLP) technique, a liquid crystal on silicon (LCoS) technique, and a micro electro mechanical systems (MEMs) micro scanner technique.
The light source of a projection apparatus may be a RGB light emitting diode (LED), a white-light LED, or a laser light source. In existing micro projection systems, a color sequential technique is broadly adopted to improve the color rendition, and LEDs in red, green, and blue colors are usually used as the light sources to provide rich colors. However, the variability is increased by using LEDs in three different colors instead of a single color, and deviation in white balance may be caused when the wavelength and brightness of the LEDs change with the temperature.